Generally, a diesel engine has excellent fuel efficiency, but exhausts materials such as nitrogen oxides (NOx) and the like. On the other hand, a gasoline engine has relatively lower fuel efficiency, but exhausts relatively fewer contaminated materials such as nitrogen oxides (NOx) and the like.
Recently, exhaust gas regulations for diesel engines have been tightened, so development of a novel diesel engine is required.
As an example of a novel diesel engine, a gasoline-diesel complex combustion engine that is driven by using a mixture of a gasoline fuel and a diesel fuel is in development.
The gasoline-diesel complex combustion engine intakes a mixture gas where the gasoline fuel and air are premixed in an intake stroke and injects the diesel fuel to control an ignition in a compression stroke. Then, the diesel fuel is compressed and ignited in an ignition stroke. At this time, the gasoline fuel is also ignited. Finally, the diesel fuel and the gasoline fuel are combusted in an explosion stroke, thereby generating driving power. However, the gasoline fuel and the diesel fuel may be ignited using a spark plug depending on a proportion of the gasoline fuel and the diesel fuel.
According to gasoline-diesel complex combustion engines of the conventional art, a single injection method has been applied when diesel fuel is injected.
However, since combustion characteristics of the gasoline-diesel complex combustion engine are different according to an engine load, fuel injection is required according to the engine load.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the disclosure and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.